I was smelling anti freeze inside the car and fully expected that the heater core was leaking. I assume the heater core is as difficult to replace as the evaporator so I put in some bars leaks. It seemed to cure the heater core problem right away. But, now I have an anti freeze leak.

The leak is coming off the passenger side pan rail along underneath the a/c compressor and along to a point a few bolts behind the compressor.

I have looked over everything in the area of the water pump very, very well, no hoses leaking, thermostat cover tight, heater line connection dry. Everything looks good.

I cannot see the water pump weep hole from underneath. I managed to get my fingers wrapped underneath the snout of the water pump, but could not feel a weep hole. The shaft looks dry.

Any ideas? The bars leaks might have attacked the seal, but I can't find the weep hole.

If it IS the water pump, I figure this is a nice swap off compared to replacing the heater core. I have had great success with Bars Leaks in the past, but the product seems to have changed, it no longer has the pellets inside.

Any thoughts or experiences would be appreciated.

Oh yeah, my Haynes manual says to move the PS pump and a/c compressor out of the way, will this really be necessary.

Thanks greatly for your replies if you have messed with these water pumps or a similar leak before.

Larry, maybe pressurizing the system will force the leak to present itself. We know 15-20 psi is safe for the system, but if you dare to perhaps overpressure the system (30psi?), the leak would be more obvious.

The heater line was the first thing that came to mind but you said you checked it. Other than using a mirror and a strong light I can only think of one other thing, and that is to go back to the heater core connections and look there. An anti-freeze smell in the cabin can almost always be traced to the heater core area. Please let us know what you end up finding!!

Thanks for all the replies, but perhaps I was not clear with the question.

The long and the short of it is that now the heater core is no longer a problem. This is on my '88 300E.

The problem is coolant dripping from along the pan rail on the passenger side directly under the a/c compressor and a few bolts back.

I cannot see the weep hole on the pump or anything else below. This area cannot be seen because the a/c compressor and other accessories obstruct it.

Has anyone ever experienced this before? I thought maybe someone, especially the pro techs may have an experience base surrounding this. I hate to buy a pump that I don't need, so I suppose I'll start tearing things out of the way and look for the leak before buying a pump.

Larry, I know that I have an M104 engine, but when I had a coolant leak that I couldn't detect, I took it to my mechanic and we put it on the lift. He took off the plastic pan, and the weep hole was in perfect view. It was coated with the residue of coolant, so I bit the bullet and had him replace it.

I have replaced the water pumps myself in virtually all of the cars I have owned (except the Ford Explorer), so I had become pretty good at it...

Larry,
Having coolant drip right off the oil pan behind the a/c comp. is
standard proceedure for a 103 waterpump. The weez hole is impossible to see without a mirror and coolant rolls right down the top of the a/c bracket and then down the block and oil pan.
the coolant usually drips off the low oil level switch as well.
Later 104 motors got a nifty collection cup under the weez hole to collect any dripping coolant. This is visible from the top.
the pumps usually leak cold and seal up shortly after warming up, so pressure test it cold.
Don't forget to check the heater pipe o-ring at the rear of the cylinder head where the hose connects to the head.
That one will send coolant down the drivers side of the block as well.

What ever happened with this waterpump? Where did you see it leaking from once it was removed? Also, did you really need the snap-on tool for the job? I need to replace the pump on my '90 300CE (w104) this weekend, and wonder whether I can get away with a wobble or flex extention from Sears?